This invention relates to a discharge device for a wire cutting machine for severing predetermined and presettable lengths of continuously fed wire. The discharge device includes a wire channel provided with a closing arrangement and a wire length detecting arrangement which is associated with the wire channel and which is operatively connected with control elements for triggering the cutting device and the closing arrangement.
German Accepted Published Patent Application (Auslegeschrift) Nos. 1,108,647 and 1,402,141 disclose apparatuses for cutting adjustable wire lengths from a continuously advanced wire wherein the shears are controlled by the wire advancing device (expediently with the aid of a steplessly variable stepdown gear) which forwards the wire to the cutting device. This operational mode has the disadvantage that the wire length to be cut is detected always indirectly and therefore slippage between the wire feeding arrangement and the wire advanced thereby constitutes an error in the length determination. The detection of wire lengths is thus effected always via that part of the endless wire which is upstream of the cutting device, so that significant deviations may occur between the "measured" wire length and the severed actual wire length.
German Accepted Published Patent Application (Auslegeschrift) No. 1,931,154 discloses a wire cutting machine in which the length detection occurs downstream of the cutting device when viewed in the direction of wire feed. For this purpose there is provided a pivotal body which has two downwardly open wire channels. The latter, at their ends oriented away from the cutting device, are provided with abutment rods which are longitudinally displaceable and length-adjustable. Further, the abutment rods are arranged to operate a switch affixed to the machine frame. In this manner the wire length entering the wire channel actuates the switch with the intermediary of the abutment rod disposed in the respective wire channel upon impact with the abutment rod. As a result of the switch actuation, a drive is energized which causes the pivotal body to swing and simultaneously, the shears coupled with the pivotal body sever the wire. By virtue of the swinging motion of the pivotal body, the severed wire portion is ejected and simultaneously, the new leading end of the wire may be introduced into the other channel. Although this arrangement which operates as a length abutment control, brings about an improvement in the uniformity of the length of the severed wire portions, it has, nevertheless, the disadvantage that the setting of the machine to different wire lengths is complicated and time consuming. The machine has to be stopped for each length adjustment, the abutment rod has to be released, adjusted and re-inserted and the new desired length has to be verified. It is a further disadvantage of this known machine that the desired wire lengths to be severed are adjustable only within relatively narrow limits, because the maximum length of the setting rods projecting freely into the wire channel is limited for reasons of stability.